The present invention relates to sprinkler units, and pertains particularly to a rotary stream sprinkler unit.
In my prior U.S. Pat. No. 3,854,664, issued Dec. 17, 1974, and, entitled "SPRINKLER SYSTEMS", I disclose a sprinkler unit which has a rotating head that directs a plurality of rotating streams over an area to be watered. In that prior device, the streams of water are formed in nozzles in the rotating head. The rotating head has inlets to the nozzle on one end which engages and cooperates with an orifice plate for acting as a valve for controlling communication of pressurized water to the nozzles
My U.S. Pat. No. 4,471,908 issued Sept. 18, 1984 and entitled "PATTERN SPRINKLER HEAD" discloses a similar sprinkler unit having V-shaped nozzles in a cylindrical rotating head The nozzle inlet openings cooperate with an orifice in an orifice plate to vary the nozzle openings to the source of pressurized water. This combination delivers streams of water of variable length and volume from the nozzles in the distributor head. The orifice opening in the plate defines the spray pattern to be produced by the streams issuing from the nozzles in the rotating head.
Among the problems of the prior device is that sand and grit from the water supply gets on the orifice plate and rapidly wears the plate and seals of the unit. In some instances, the sand and grit can cause the unit to stall. These and other problems of the prior device have prevented it from being satisfactory.
In my co-pending application Ser. No. 878,591, filed June 26, 1986, entitled "ROTARY STREAM SPRINKLER UNIT", I disclose a sprinkler unit, that is an improvement of the aforementioned patent, that utilizes an open channel head for directing the streams. It also utilizes specially configured passages or nozzles to form and control each of the streams to the channels in the head. It has been found that the passages are subject to plugging due to particles of sand and the like in the water.
Accordingly, it is desirable that an improved rotary stream sprinkler unit be available.